Coaxial fan mechanism for low-speed large-torque direct-drive permanent magnet synchronous motor

Abstract

The invention relates to the technical field of heat dissipation of permanent magnet synchronous motors, in particular to a coaxial fan mechanism for a low-speed large-torque direct-drive permanent magnet synchronous motor. Comprising a motor body, a coaxial connection auxiliary shaft, a coaxial fan set and a fan cover, after the motor is started, a main shaft drives the coaxial fan set to rotate through the coaxial connection auxiliary shaft, a reversing mechanism ensures that a variable-diameter fan and an exhaust fan rotate in opposite directions, and the variable-diameter fan automatically adjusts the blade angle according to the rotating speed so as to change the air volume. External cold air is sucked from the air inlet in the end face of the fan cover, forms forced airflow under the action of the coaxial fan set, and finally is accurately guided to the heat dissipation surface of the motor shell through the flow guide window, a large amount of heat is taken away, and effective cooling of the motor is achieved.

Description

Technical Field

[0001] This invention relates to the field of heat dissipation technology for permanent magnet synchronous motors, and specifically to a coaxial fan mechanism for a low-speed, high-torque direct-drive permanent magnet synchronous motor. Background Technology

[0002] To directly output high torque, low-speed, high-torque direct-drive permanent magnet synchronous motors are typically designed to be large, resulting in a relatively small ratio of heat dissipation surface area to internal heat loss. Simultaneously, when operating at low speeds, the air pressure and airflow generated by the built-in fan on the rotor are severely insufficient to effectively break the "static air boundary layer" on the motor casing surface, leading to a sharp decline in heat dissipation efficiency. Under continuous high load conditions, heat accumulates inside the motor, easily causing irreversible demagnetization of the permanent magnets and accelerated aging of insulation materials, seriously threatening the motor's service life and operational reliability.

[0003] To solve the aforementioned heat dissipation problem, existing technologies typically employ the following solutions: Additional independent cooling fan: A small axial fan driven by a separate motor is installed on the non-drive end of the motor for forced air cooling. While this solution provides some cooling effect, it increases energy consumption, installation space, control circuitry, and potential points of failure, contradicting the high integration and high reliability design principles of direct-drive motors.

[0004] Complex water-cooling systems: For motors with extremely high power density, a solution is to install cooling water channels inside the motor housing. Although water cooling is highly efficient, the system structure is complex and costly, there is a risk of water leakage, and it requires matching water pumps, water tanks, and heat exchangers, resulting in high maintenance requirements and poor applicability in many industrial applications.

[0005] Non-shaft-driven air-cooled structures: Some designs attempt to install fan blades on the motor spindle, but the airflow path generated by the fan blades is chaotic and fails to form an effective, directional forced convection channel with the motor housing. The airflow often just skims over the motor surface, failing to efficiently carry away heat, resulting in limited improvement in heat dissipation, and easily drawing dust and debris from the environment into the motor.

[0006] Therefore, there is an urgent need for a cooling solution that can be linked to the host machine's rotation speed, has adaptive heat dissipation efficiency, and is compact in structure. Summary of the Invention

[0007] The purpose of this invention is to solve the problems in the background art and provide a coaxial fan mechanism for a low-speed, high-torque direct-drive permanent magnet synchronous motor.

[0008] The above-mentioned technical objective of the present invention is achieved through the following technical solution: A coaxial fan mechanism for a low-speed, high-torque direct-drive permanent magnet synchronous motor includes: a motor body, a coaxial connecting sub-shaft, a coaxial fan assembly, and a fan cover; The motor body includes a motor housing and a main shaft. The main shaft includes a driving end and a non-driving end. The driving end is located at the head of the motor body, and the non-driving end is located at the tail of the motor body. The coaxial connecting sub-shaft is coaxially and fixedly connected to the non-driving end of the main shaft. The coaxial fan assembly is connected to the main shaft through the coaxial connecting sub-shaft. Both the coaxial fan assembly and the fan cover are located at the tail of the motor housing.

[0009] Preferably, the coaxial fan assembly includes a variable diameter fan and an exhaust fan, wherein the variable diameter fan is disposed on the side closer to the non-driving end, and the exhaust fan is disposed on the side away from the non-driving end, and the variable diameter fan and the exhaust fan are coaxially reverse-propeller configured; a reversing mechanism is provided between the variable diameter fan and the exhaust fan.

[0010] By combining a variable diameter fan with an exhaust fan and using a coaxial reverse propeller design, the two fans work together to more efficiently guide and transport cool ambient air, thereby improving the overall cooling airflow and pressure.

[0011] Preferably, the reversing mechanism includes: a reversing coupling base, a first bevel gear, a second bevel gear, and a reversing bevel gear; the first bevel gear is coaxially connected to the variable diameter fan, and the second bevel gear is coaxially connected to the exhaust fan; the first bevel gear, the second bevel gear, and the reversing bevel gear are all disposed in the reversing coupling base and mesh perpendicularly with each other.

[0012] The vertical meshing of three bevel gears, along with the transition of the phase bevel gear, ensures that the two fans achieve precise and stable counter-rotation.

[0013] Preferably, the variable diameter fan includes: rotating blades, a fan hub, and a centrifugal tension spring; the bottom of the rotating blades is hinged to the fan hub, and the two ends of the centrifugal tension spring are respectively connected to the rotating blades and the fan hub.

[0014] Preferably, the bottom of the rotating blade is provided with a first hinge point, and the rim of the fan hub is provided with a plurality of hinge pins evenly distributed. The bottom of the rotating blade is hinged to the hinge pins on the fan hub by a shaft pin.

[0015] Preferably, a first spring anchor point is provided on the end face of the fan hub, a second spring anchor point is provided in the middle of the rotating blade, and the two ends of the centrifugal tension spring are respectively fixed to the first spring anchor point and the second spring anchor point.

[0016] By hinged to the centrifugal tension spring and rotating blades, the fan can automatically change its diameter according to the rotation speed, thereby meeting the motor's heat dissipation requirements under different operating conditions.

[0017] Preferably, a limiting mechanism is provided between the rotating blade and the fan hub. The limiting mechanism includes a limiting slot provided at the rotating blade and a limiting boss provided on the fan hub. The top of the limiting boss is inserted into the limiting slot, and the bottom of the limiting boss is fixedly connected to the fan hub.

[0018] By setting limit slots and limit bosses, a clear mechanical stop point is set for the rotation angle of the rotating blades, preventing the rotating blades from rotating beyond the limit under centrifugal force, ensuring that they always operate within the safe range during the diameter change process, and effectively avoiding overload stretching of the centrifugal tension springs.

[0019] Preferably, the diameter of the fan cover is larger than the diameter of the motor housing; a plurality of air inlets are provided on the side of the fan cover away from the motor housing, and the air inlets are evenly distributed along the end face of the fan cover; a plurality of air guide windows are provided on the side of the fan cover near the motor housing, and the outlet direction of the air guide windows is towards the heat dissipation fins of the motor housing.

[0020] By combining the air inlet and the air guide window, the cooling airflow can be concentrated and directed to the surface of the heat dissipation fins on the motor housing. The fan cover diameter is larger than the motor housing, providing ample air intake area.

[0021] In summary, the beneficial effects of this invention are as follows: 1. The coaxial fan mechanism for a low-speed, high-torque direct-drive permanent magnet synchronous motor described in this invention directly drives the fan by utilizing the output power of the motor's main shaft through a coaxial connection to the secondary shaft. It does not require an additional independent fan motor and a complex transmission system, has a compact structure, saves installation space, and is particularly suitable for direct-drive applications with limited space. 2. The coaxial fan mechanism for a low-speed, high-torque direct-drive permanent magnet synchronous motor described in this invention, wherein when the motor is running at low speed, the variable-diameter fan is in a small-diameter fan state, matching the heat dissipation requirements of the low-heat motor; when the motor speed increases, the variable-diameter fan blades increase the fan area under the action of centrifugal force, so that the heat dissipation covers the side wall of the motor housing, thereby matching the heat dissipation requirements of the motor under high power conditions. This perfectly solves the contradiction that traditional fixed-blade fans cannot simultaneously meet both high and low speed requirements. 3. The coaxial fan mechanism for a low-speed, high-torque direct-drive permanent magnet synchronous motor described in this invention actively increases the air intake volume at the center of the fan assembly by using a coaxial reverse-propeller-configured exhaust fan, effectively ensuring the overall airflow and heat dissipation effect of the fan assembly. Attached Figure Description

[0022] Figure 1This is a cross-sectional view of the coaxial motor fan in this invention; Figure 2 This is a schematic diagram of the variable diameter fan in its retracted state according to the present invention; Figure 3 This is a schematic diagram of the variable diameter fan in the deployed state of the present invention; Figure 4 This is a schematic diagram of the inverted structure in this invention; Figure 5 This is a schematic diagram of the exhaust fan in this invention; The markings in the diagram are: 1-motor body, 11-motor housing, 12-main shaft, 2-coaxial connecting secondary shaft, 31-variable diameter fan, 32-exhaust fan, 311-rotating blades, 312-fan hub, 313-centrifugal tension spring, 3111-second spring anchor point, 3112-first hinge point, 3121-hinge column foot, 3122-first spring anchor point, 3011-limiting slot, 3012-limiting boss, 4-fan cover, 41-air inlet, 42-guide window, 5-reversing mechanism, 51-reversing coupling base, 52-first bevel gear, 53-second bevel gear, 54-reversing bevel gear. Detailed Implementation

[0023] The following specific embodiments are merely illustrative of the present invention and are not intended to limit the invention. Those skilled in the art can make modifications to these embodiments without contributing any inventive step after reading this specification, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

[0024] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0025] Example 1:

[0026] like Figures 1-5 As shown, a coaxial fan mechanism for a low-speed, high-torque direct-drive permanent magnet synchronous motor includes: a motor body, a coaxial connecting sub-shaft, a coaxial fan assembly, and a fan cover; like Figure 1 As shown, the motor body includes a motor housing and a main shaft. The main shaft includes a drive end and a non-drive end. The drive end is located at the head of the motor body, and the non-drive end is located at the tail of the motor body. A coaxial connecting sub-shaft is coaxially and fixedly connected to the non-drive end of the main shaft. The coaxial fan assembly is connected to the main shaft through the coaxial connecting sub-shaft. Both the coaxial fan assembly and the fan cover are located at the tail of the motor housing.

[0027] like Figure 1As shown, the coaxial fan assembly includes a variable diameter fan and an exhaust fan. The variable diameter fan is located on the side closer to the non-drive end, and the exhaust fan is located on the side farther from the non-drive end. The variable diameter fan and the exhaust fan are coaxially reversed. A reversing mechanism is provided between the variable diameter fan and the exhaust fan.

[0028] like Figure 4 As shown, the reversing mechanism includes: a reversing coupling base, a first bevel gear, a second bevel gear, and a reversing bevel gear; the first bevel gear is coaxially connected to the variable diameter fan, and the second bevel gear is coaxially connected to the exhaust fan; the first bevel gear, the second bevel gear, and the reversing bevel gear are all disposed in the reversing coupling base and mesh perpendicularly with each other.

[0029] A key aspect of this embodiment lies in the design of the variable diameter fan, such as... Figures 2-3 As shown, the variable diameter fan includes: rotating blades, a fan hub, and a centrifugal tension spring. The bottom of the rotating blades is hinged to the fan hub, and both ends of the centrifugal tension spring are connected to the rotating blades and the fan hub, respectively. A first hinge point is provided at the bottom of the rotating blades, and several hinge pins are evenly distributed on the rim of the fan hub. The bottom of the rotating blades is hinged to the hinge pins on the fan hub via a pivot pin. A first spring anchor point is provided on the end face of the fan hub, and a second spring anchor point is provided in the middle of the rotating blades. Both ends of the centrifugal tension spring are fixed to the first spring anchor point and the second spring anchor point, respectively.

[0030] like Figures 2-3 As shown, to prevent the blades from opening too wide, a limiting mechanism is provided between the rotating blades and the fan hub. This limiting mechanism includes a limiting slot at the rotating blade and a limiting boss on the fan hub. The top of the limiting boss is inserted into the limiting slot, and the bottom of the limiting boss is fixedly connected to the fan hub. When the blades swing, the wall of the limiting slot contacts the limiting boss, thereby limiting the extreme opening angle of the blades and ensuring operational safety.

[0031] like Figure 1 As shown, the diameter of the fan cover is larger than the diameter of the motor housing; several air inlets are provided on the side of the fan cover away from the motor housing, and the air inlets are evenly distributed along the end face of the fan cover; several guide windows are provided on the side of the fan cover near the motor housing, and the outlet direction of the guide windows is towards the heat dissipation fins of the motor housing.

[0032] A brief description of the working principle of a coaxial fan mechanism for a low-speed, high-torque direct-drive permanent magnet synchronous motor: After the motor starts, the main shaft drives the coaxial fan assembly to rotate via a coaxial connection to the secondary shaft. A reversing mechanism ensures that the variable-diameter fan and the exhaust fan rotate in opposite directions. The variable-diameter fan automatically adjusts its blade angle according to the rotational speed to change the airflow. When the motor is operating at low speed, the centrifugal force is small, and the tension of the centrifugal spring keeps the rotating blades in a retracted state, resulting in a smaller fan diameter and lower operating resistance, which is beneficial for motor startup. As the motor speed increases, the centrifugal force increases. When the centrifugal force exceeds the preload of the tension spring, the rotating blades begin to open outward, increasing the fan's sweeping area and airflow to meet the greater heat dissipation requirements at high speeds. External cold air is drawn in through the air inlet on the fan shroud end face, and through the action of the coaxial fan assembly, forms a forced airflow. Finally, it is precisely guided through the guide window to the heat dissipation surface of the motor housing, carrying away a large amount of heat and achieving effective cooling of the motor.

Claims

1. A coaxial fan mechanism for a low-speed, high-torque direct-drive permanent magnet synchronous motor, characterized in that, include: Motor body (1), coaxial connecting sub-shaft (2), coaxial fan assembly (3) and fan cover (4); The motor body (1) includes a motor housing (11) and a main shaft (12). The main shaft (12) includes a driving end (121) and a non-driving end (122). The driving end (121) is located at the head of the motor body (1), and the non-driving end (122) is located at the tail of the motor body (1). The coaxial connecting sub-shaft (2) is coaxially fixedly connected to the non-driving end (122) of the main shaft (12). The coaxial fan assembly (3) is connected to the main shaft (12) through the coaxial connecting sub-shaft (2). The coaxial fan assembly (3) and the fan cover (4) are both located at the tail of the motor housing (11).

2. The coaxial fan mechanism for a low-speed, high-torque direct-drive permanent magnet synchronous motor according to claim 1, characterized in that, The coaxial fan assembly (3) includes a variable diameter fan (31) and an exhaust fan (32). The variable diameter fan (31) is located on the side close to the non-drive end (122), and the exhaust fan (32) is located on the side away from the non-drive end (122). The variable diameter fan (31) and the exhaust fan (32) are coaxially reversed. A reversing mechanism (5) is provided between the variable diameter fan (31) and the exhaust fan (32).

3. A coaxial fan mechanism for a low-speed, high-torque direct-drive permanent magnet synchronous motor according to claim 2, characterized in that, The reversing mechanism (5) includes: a reversing coupling base (51), a first bevel gear (52), a second bevel gear (53), and a reversing bevel gear (54); the first bevel gear (52) is coaxially connected to the variable diameter fan (31), the second bevel gear (53) is coaxially connected to the exhaust fan (32), and the first bevel gear (52), the second bevel gear (53), and the reversing bevel gear (54) are all disposed in the reversing coupling base (51) and mesh perpendicularly with each other.

4. A coaxial fan mechanism for a low-speed, high-torque direct-drive permanent magnet synchronous motor according to claim 2, characterized in that, The variable diameter fan (31) includes: a rotating blade (311), a fan hub (312), and a centrifugal tension spring (313); the bottom of the rotating blade (311) is hinged to the fan hub (312), and the two ends of the centrifugal tension spring (313) are respectively connected to the rotating blade (311) and the fan hub (312).

5. A coaxial fan mechanism for a low-speed, high-torque direct-drive permanent magnet synchronous motor according to claim 4, characterized in that, The bottom of the rotating blade (311) is provided with a first hinge point (3112), and the rim of the fan hub (312) is evenly provided with a number of hinge pins (3121). The bottom of the rotating blade (311) is hinged to the hinge pins (3121) on the fan hub (312) by means of a shaft pin.

6. A coaxial fan mechanism for a low-speed, high-torque direct-drive permanent magnet synchronous motor according to claim 5, characterized in that, A first spring anchor point (3122) is provided on the end face of the fan hub (312), a second spring anchor point (3111) is provided in the middle of the rotating blade (311), and the two ends of the centrifugal tension spring (313) are respectively fixed to the first spring anchor point (3122) and the second spring anchor point (3111).

7. A coaxial fan mechanism for a low-speed, high-torque direct-drive permanent magnet synchronous motor according to claim 4, characterized in that, A limiting mechanism (301) is provided between the rotating blade (311) and the fan hub (312). The limiting mechanism (301) includes a limiting slot (3011) provided at the rotating blade (311) and a limiting boss (3012) provided on the fan hub (312). The top of the limiting boss (3012) is inserted into the limiting slot (3011), and the bottom of the limiting boss (3012) is fixedly connected to the fan hub (312).

8. A coaxial fan mechanism for a low-speed, high-torque direct-drive permanent magnet synchronous motor according to claim 1, characterized in that, The diameter of the fan cover (4) is larger than the diameter of the motor housing (11); a plurality of air inlets (41) are provided on the side of the fan cover (4) away from the motor housing (11), and the air inlets (41) are evenly distributed along the end face of the fan cover (4); a plurality of guide windows (42) are provided on the side of the fan cover (4) close to the motor housing (11), and the outlet direction of the guide windows (42) is towards the heat dissipation fins of the motor housing (11).

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